The present invention relates generally to farm implements and, more particularly, to a lockout system for hydraulic valves of an agricultural implement, such as a hoe drill, to prevent unintentional lowering of ground engaging tools of the hoe drill when the drill is in, or is being transitioned to, a folded, transport position.
Modern farmers strive to improve the management of the increasing amounts of farm acres. Improving management requires farmers to be able to quickly prepare the soil and plant seed each season. This haste has driven the need for more efficient and larger agricultural machinery.
Implements such as harrows, packers, or combined harrow-packers are being made with widths exceeding sixty feet in the field operating position. Also, drill implements employed to distribute seed product across an agricultural field are also being made increasingly wider in the field operating position. Wider working widths provide more efficient field working by increasing the number of rows that are seeded in a single pass or by increasing the amount of field that is tilled in a single pass. However, as agricultural implements have been made increasingly wider, there has been a need for systems to compactly fold the implement for practical and safe transport over highways and through gates, and for greater maneuverability.
An implement, such as a hoe drill, will typically be hydraulically folded between the extended, field working position and the narrow transport position. The hydraulic system generally consists of hydraulic actuators and valves that control the flow of hydraulic fluid in the actuators. The valves are commonly mechanically coupled to control levers that can be manually actuated by an operator.
To fold the implement from the extended, field working position to the narrow transport position, the operator moves a two-position control lever of the implement to a transport position which in turn changes the hydraulic valves for the implement to a transport position or setting. Thus, when the hydraulic system for the implement is activated, such as by a hydraulic remote in the operator cab of the prime mover, the implement will fold to the transport position. Similarly, to unfold the implement, the hydraulic system is activated to unfold the implement. However, the ground openers mounted to the frame of the implement cannot be lowered into a ground engaging position until the control lever is moved to the field position or setting. When the control lever is in the field position, the implement frame is free to pivot about a transverse axis to respond to changes in terrain contour as the implement is being towed along the field. An undesirable condition can occur however if the implement is in transition to, or already in, the transport position and the valves are switched to the field setting. That is, the implement could pivot about the transverse axis and lower without any control.